Flu Vaccines Expire on June 30th

Expired influenza vaccines might not protect people against the current flu season viruses

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Every year, the injectable inactivated influenza vaccine (IIV) has a standard expiration date of June 30 for the Northern Hemisphere influenza season.

This Centers for Disease Control and Prevention (CDC) statement on June 13, 2019, means ‘vaccination with an expired influenza vaccine might not protect against influenza infection because different influenza virus strains can be included in the vaccine each year.

The new year for flu vaccines starts on July 1st each year.

In addition, protection against the various influenza viruses included in the vaccine could wane if vaccine potency decreases over time.

In most VAERS reports, factors that contributed to the administration of expired vaccine were not specified. However, seven reports detailed that patients were offered revaccination with the current season’s influenza vaccine; of these, three confirmed revaccinations.

As a spontaneous reporting surveillance system, VAERS likely captures only a small fraction of expired IIV administered; therefore, this error might be more common than VAERS data indicate.